Synthesis, structures and electrocatalytic properties of coordination polymers of 4,4′,4′′,4′′′-tetrakiscarboxyphenylsilane and 1,3,5-tris(2-methyl-1H-imidazol-1-yl)benzene

Abstract

Four Ni, Co, Cu, Zn-containing coordination polymers incorporating 4,4′,4′′,4′′′-tetrakiscarboxyphenylsilane (H₄tcps) and 1,3,5-tris(2-methyl-1H-imidazol-1-yl)benzene (tmib) ligands, namely [Ni₆(tcps)₃(tmib)₄(H₂O)₂] (1), [Co₆(tcps)₃(tmib)₄] (2), [Cu₂(tcps)(tmib)(H₂O)] (3) and [Zn₂(tcps)(tmib)] (4), were synthesized by the solvothermal method. Compounds 1 and 2 were isostructural with three-dimensional (3D) (3,4)-connected frameworks. Compounds 3 and 4 possessed (3,4)-connected 3D networks with (6·8²)(6·8⁵)(6²·8²·10²)(6²·8) and (4·6·8)(4·6³·8²)(6⁶)(6⁷·8³) topology, respectively. The thermal derivatives of compounds 1 and 2, Co-800 and Ni-700, exhibited low OER overpotentials of 338 and 388 mV to achieve a current density of 10 mA cm⁻² and hold their electrocatalytic activity for at least 9 hours in 1 M KOH.